Firearms are commonly used in industries such as the military, law enforcement, security, hunting and recreational target shooting. Many of today's firearms operate through the coordinated actions of an ammunition magazine and a bolt carrier.
Ammunition magazines store and feed multiple cartridges of ammunition while within or attached to a firearm. Ammunition magazines are generally made of metal or plastic, and they may be straight or curved. Magazines carry multiple cartridges of ammunition and allow the user to carry around the magazines themselves instead of loose cartridges. Perhaps the most common type of magazine today is the detachable box type. The detachable box type magazine has several benefits, including allowing the user to conveniently remove spent magazines and replace them with loaded magazines.
The detachable box type magazine comprises a container for storing ammunition. The container has a bottom end and an open top end, where the top end attaches to the firearm via a slot in the firearm's lower receiver. A spring-loaded follower for feeding ammunition cartridges is provided in the interior of the container. When ammunition is loaded into the magazine, it compresses the spring and pushes the follower downwards towards the bottom end. Cartridges may be stored in a column, usually with one above the other or staggered in a zig zag fashion. As the top cartridge is expended, the spring pushes the follower, as well as the ammunition on top of the follower, upwards towards the open top end of the magazine. The next cartridge is thus positioned to be loaded into the firearm's chamber.
In many firearms, when a new cartridge is pushed upwards to the top end of the magazine, a tubular bolt carrier is used to drive the cartridge forward into the chamber. A recess in the bolt face of the bolt carrier grips the back end of the cartridge. When the bullet is fired, it is expelled from the cartridge and rides down and out the barrel of the firearm. An empty cartridge case is left behind and held by the bolt face. Pressure, such as gas pressure from the firing of the bullet, causes the bolt carrier to move backwards taking the empty cartridge case with it. The empty cartridge case may be ejected out a port opening in the firearm or manually removed.
When the magazine is empty, a bolt catch is often used to retain the bolt carrier in a rearward position and prevents it from engaging the chamber. This allows the user to remove the spent magazine and replace it with a loaded magazine.
Unfortunately, the process of replacing an empty magazine with a loaded magazine requires multiple steps and is time consuming. Generally, the following steps are required:
Visually check that the magazine is out of ammunition and that the firearm has not jammed;
Remove empty magazine from the lower receiver of the firearm;
Insert loaded magazine into the lower receiver of the firearm;
Cycle the bolt carrier to chamber the first round of ammunition; and
Re-acquire the intended target for engagement.
In the many different critical and dangerous situations which can be faced by users in the military, law enforcement, security and even hunting, time is limited. Users must replace the empty magazine as quickly and efficiently as possible. Any features in the firearm that can automate, streamline, speed up or simplify any of these steps involved in reloading the firearm would be advantageous.
Most firearms have control features whereby a user can manually: (i) eject a magazine; (ii) release the bolt catch to allow the bolt carrier to move forward; and/or (iii) engage the bolt catch to retain the bolt carrier in the rearward position. Known firearms including the AR-15, M16 and M4 have such manual controls on only one side of the firearm. For example, many standard embodiments have the manual magazine release control on the right side only and the manual bolt catch controls on the left side only.
Many firearms also have a charging handle. This may be a protrusion or hook formed from the side of the bolt carrier or a lever. A charging handle allows the user to manually pull the bolt carrier rearwards. For example, the charging handle may be used to eject an empty cartridge case or unfired cartridge from the chamber, to load a round from the magazine, to clear a jam or double feed or to release the bolt carrier from being retained in the rearwards position. In cases where a jam occurs which requires clearing or the firearm needs to be cleaned or inspected, the bolt carrier needs to be moved rearwards and the charging handle is used to accomplish this.
Charging handles often protrude out one side of the firearm and are therefore, susceptible to getting caught on objects and getting damaged. Furthermore, many charging handles are not sufficiently large or easy to grip by users, such as users who are wearing gloves or protective clothing. Also charging handles are only generally operable from one side of the firearm.
Most users are not ambidextrous and therefore, will generally find it more difficult to operate a control present on only one of the two sides of the firearm. Alternatively, in critical and dangerous situations which can be faced by a user, the user's access to one side of the firearm may be obstructed or hampered. For example, one of the user's hands or arms may be physically injured and have difficulty accessing one side of the firearm. In addition, in a critical and dangerous situation, it may be important for the user's self defence to keep a finger of his or her preferred hand on the trigger while operating the firearm's various controls with his or her opposing hand. Therefore, a firearm which provides for ambidextrous operation of its controls would be beneficial.
Bolt catch release levers are available which extend around the outside of the lower receiver from one side to the other side. This allows the user to release the bolt catch manually from either side of the firearm. Typically, these pass through the trigger area and can interfere with gloved operation. Unfortunately, such a device which extends around the exterior of the firearm is susceptible to damage, getting caught on other objects and so on. Other solutions which provide for user control on both sides of the firearm require a modified lower receiver to be compatible. This is not only costly and complex to do, but also undesirable because the lower receiver is often the registered part of the firearm and is preferably not replaced.
It would be beneficial to have features on the firearm that allow a user to quickly, conveniently and manually: (i) eject the magazine; (ii) release the bolt catch to allow the bolt carrier to move forward; (iii) engage the bolt catch to retain the bolt carrier in the rearward position; and/or (iv) operate the charging handle, on either side of the firearm.